Illuminated caliper instrument

ABSTRACT

An illuminated caliper device includes a caliper assembly having first and second caliper legs each having a pointed tip and a pivot end. A pivot support and first and second pivot elements pivotally connects the pivot ends of the first and second caliper legs to the pivot support. A battery housing attached to the pivot support contains a battery. First and second light emitting diodes are coupled by a switch mounted on the battery housing to first and second terminals of the battery and produced light that is directed to areas of the surface to be measured by pointed tips of the legs. The intensity and color of light emitted by the first light emitting diode are such as to sufficiently illuminate the surface under low ambient illumination conditions without disrupting acquired night vision of a user.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of prior filed co-pending U.S.provisional application Ser. No. 60/301,533 filed Jun. 27, 2001 entitled“ILLUMINATED CALIPER INSTRUMENT” by Robert A. Mackin and Jeffrey M.Mackin.

BACKGROUND OF THE INVENTION

The invention relates to calipers or caliper instruments (also sometimesreferred to as dividers) of the type utilized by persons who work indark environments, for example paramedics needing to make measurementson a medical chart plotted by a heart monitoring instrument under “fieldconditions”, navigators, aviators, and other persons who must measurethe distance between two points of a chart plotted by an instrument, amap, or other document under very low ambient illumination conditions.It is important that the “night vision” of such persons not betemporarily disrupted by the presence of unnecessarily bright “white”light on the document (or other surface) to allow measurement of thedistance between two points on the document. A person whose eyes areopen for approximately 15 to 20 minutes under dark conditions or verylow ambient illumination conditions acquires what is known as “nightvision”, wherein the person's eyes become much more sensitive to lowlevels of ambient illumination. If the eyes of a person who has acquirednight vision are suddenly subjected to relatively bright light,especially white light, the person is subjected to what is referred toas “night blindness”, wherein the acquired night vision is lost. Theperson then must reacquire his/her night vision by remaining in no-lightor very low-light conditions for another 15 to 20 minutes, during whichhe or she may be unable to recognize critically important things oroccurrences in the low ambient light conditions in which the person isworking.

Although a need for solving this problem has existed for long time, nopractical means for solving the problem, such as a compact, reasonablyinexpensive illuminated caliper instrument, has been provided.

U.S. Pat. No. 5,115,571, issued May 26, 1992, by present inventor RobertA. Mackin, discloses a caliper instrument including a gear mechanismwherein the upper ends of the caliper legs are interlocked by gear teethso that the caliper legs of the symmetrically in opposite directionsabout a bisection axis.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to provide a caliperinstrument which provides adequate illumination to a person workingunder night conditions for very low ambient illumination conditions forutilization of a caliper instrument to measure or delineate the distancebetween points on a document or object without impairing the nightvision of the person measuring coordinating the distance between thepoints.

Briefly described, and in accordance with one embodiment thereof, theinvention provides a caliper instrument including a light emittingdiode, a battery, and an on/off switch contained/installed in a hub ofthe illuminated caliper instrument from which its caliper legs extend.The light emitting diode is oriented to illuminate an area on thedocument including a pair of points the distance between which is to bemeasured or delineated the by needle points of the caliper instrument.In one described embodiment, two light emitting diodes, preferably redlight emitting diodes or green light emitting diodes, arecontained/installed in/on the hub of the caliper instrument. The opticalaxis of one of the light emitting diodes is oriented at a predeterminedangle relative to a bisection axis of the optical instrument, and theoptical axis of the other light emitting diode is oriented at anasymmetrically opposite angle relative to the bisection axis, so thatpoints of the document touched by the needle points of the caliperinstrument when its caliper legs are opened wide are equally andadequately illuminated. In one embodiment, the light emitting diodes aremounted directly on lower portions of the legs to direct the lightprecisely to areas of the document or object to be measured by theneedle points. In another embodiment, fiber optic elements extendbetween each light emitting diode and a corresponding fiber optic lensattached to a lower portion of a corresponding leg.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of one embodiment of the illuminatedcaliper instrument of the present invention, in an open configuration.

FIG. 2 is an elevational view of the caliper instrument of FIG. 1 in aclosed configuration with a protective cap installed.

FIG. 3 is a side elevational view of the illuminated caliper instrumentof FIG. 1.

FIG. 4 is a partial exploded elevational view of the upper portion ofthe illuminated caliper instrument of FIG. 1.

FIG. 5 is a top view of a battery housing of the illuminated caliperinstrument of FIG. 1.

FIG. 6 is bottom view of the illuminated caliper instrument of FIG. 1with its caliper legs spread wide open.

FIG. 7 is a schematic diagram of the circuitry including the battery,switch assembly and light emitting diodes in the illuminated caliperinstrument of FIG. 1.

FIG. 8 is a front elevational view of another embodiment of theilluminated caliper instrument of the present invention in which thelight emitting diodes are attached to lower portions of the caliperlegs.

FIG. 9 is a front elevational view of one embodiment of the illuminatedcaliper instrument of the present invention in which fiber optic bundlesare coupled between the light emitting diodes and corresponding fiberoptic lens attached to lower portions of the caliper legs.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, illuminated caliper instrument 1 includes a hub 100from which a pair of caliper legs 4 and 5 downwardly extend. Hub 100includes an upper section 2 and a lower section 3. A pair of needles 6and 7 extend downwardly from the lower ends of legs 4 and 5,respectively. Legs 4 and 5 are attached to a gear mechanism 36 in lowersection 3 (see the bottom view shown in FIG. 6) which can be essentiallyidentical to that disclosed in the above referenced U.S. Pat. No.5,115,571, so that when the caliper legs 4 and 5 are pivoted about pivotends 3A and 3B so that caliper legs 4 and 5 are “opened” or “closed” asindicated by are 8, the movement of each leg 4 and 5 is symmetricallyopposite with reference to a bisection axis 9. (Alternatively, the upperends of legs 4 and 5 can be pivotally attached to hub 100 without use ofgear mechanism 36.)

Lower section 3 includes the above-mentioned gear mechanism 36, whichincludes two engaged gears attached to the upper ends 28 of caliper legs4 and 5, which are pivotally connected to a gear housing 10. An annularcap retaining ring 12 is rigidly attached to and disposed around theperiphery of the upper portion of gear housing 10. The plane ofretaining ring 12 is perpendicular to bisection axis 9. An O ring 11 isdisposed in a groove (not shown), the plane of which is parallel to theplane of cap retaining ring 12.

Upper section 2 includes a cylindrical battery housing 13 into which aswitch mechanism 16 having outer threads 30 is threaded. Switchmechanism 16 includes a suitable switch control element 17, which can bea rotary device or a depressible switch button or the like.

As shown in FIG. 2, when legs 4 and 5 are in a “closed” configuration,i.e., have been moved close to each other so that both are parallel tobisection axis 9, then a protective cylindrical cap 20 can be slid overO ring 11 and abutted against the lower edge of annular cap retainingring 12. A suitable pocket clip 14 can be attached to the lower end ofprotective cap 20 as shown in FIG. 2, wherein reference numeral 1Adesignates the illuminated caliper instrument 1 with protective cap 20in place. If desired, pocket clip 14 can instead be provided at theupper end of protective cap 20 as indicated by dotted lines 14A.

Referring to FIGS. 1 and 3, a first light emitting diode 22 and a secondlight emitting diode 23 are powered by the battery 32 (FIG. 5) retainedin battery housing 13 when switch mechanism 16 is actuated or turned on.Battery 32 can be a suitable, readily available hearing aid type ofbattery or button-type battery.

First light emitting diode 22 is installed at the bottom portion of gearhousing 10 adjacent to the left side of legs 4 and 5 as shown in FIGS. 1and 3, so that the optical axis of light emitting diode 22 is generallyoriented in a direction indicated by arrow 25, so as to adequatelyilluminate a portion of a document or other surface (not shown) to becontacted by the tip of needle 6 when legs 4 and 5 are spread fairly farapart. Similarly, second light emitting diode 23 is installed on theright side of legs 4 and 5 as shown in FIG. 3, so that the optical axisof light emitting diode 23 is generally oriented in a directionindicated by arrow 26, so as to adequately illuminate a portion of thedocument or surface to be contacted by the tip of needle 7 when legs 4and 5 are spread fairly far apart.

Light emitting diodes 22 and 23 can be, for example, red light emittingdiodes or green light emitting diodes of recent high-intensity design.In recent years, low-power light emitting diodes of sufficiently highintensity to illuminate a document for reading purposes have becomeavailable. Such light emitting diodes are available in both red andgreen colors, which are less likely to interfere with the night visionof a person such as a paramedic, navigator, aviator astronomer, or thelike who is working in darkness or in low ambient light conditions andis depending on his/her “night vision” to accomplish his/her work.

Therefore, when such person turns on light emitting diodes 22 and 23 ofilluminated caliper instrument 1 to measure the distance between twopoints on the document, the intensity of the illumination produced onthe document by light emitting diodes 22 and 23 does not appreciablyinterfere with the person's night vision because the light is directedto the document or surface rather than to the person's eyes. Thesignificantly reduces the chance of the person undergoing nightblindness.

Referring to FIGS. 4 and 5, the switch mechanism 16 has peripheralthreads 30 disposed on its lower portion. The external threads 30 matewith internal threads 34 of battery housing 13, so switch assembly 16can be threaded into battery housing 13 when battery 32 is in placewithin battery housing 13.

FIG. 7 shows the schematic diagram of the light emitting diodes 22 and23, switch assembly 16, and battery 32 referred to above. Battery 32actually is composed of several button type batteries stacked in series.The (+) terminal of battery 32 is connected to one terminal of switchassembly 16, the other terminal of which is connected to the anodes oflight emitting diodes 22 and 23. The cathodes of light emitting diodes22 and 23 are connected to the negative terminal of battery 32.(Alternatively, light emitting diodes 22 and 23 could be connected inseries.)

In another embodiment, light emitting diodes 22 and 23 are attacheddirectly to upper portions of caliper legs 4 and 5, respectively, sothat the optical axes of the two light emitting diodes change directionalong with the longitudinal axes caliper legs 4 and 5, respectively, asthey are moved in the directions indicated by are 8.

In another embodiment 1B shown in FIG. 8, light emitting diodes 22 and23 are attached directly to lower ends of caliper legs 4 and 5,respectively, so that the optical axes of the two light emitting diodeschange direction along with the longitudinal axes of caliper legs 4 and5, respectively, as they are moved in the directions indicated by are 8.The shorter distances between the between the light emitting diodes andthe document or object to be measured results in increased illuminationthereof. In this case, two pairs of electrical conductors 55 and 56extending along caliber legs and 5 and 4, respectively, couple lightemitting diodes 22 and 23, respectively, to switch mechanism 16 andbattery 32.

In another alternative embodiment 1C shown in FIG. 9, two pairs of fiberoptic bundles 51 and 52 extend along caliper legs 5 and 4, respectively,to couple light emitting diodes 22 and 23 to fiber optic lenses 62 and61 which are respectively attached to the lower ends of caliper legs 5and 4. This arrangement directs the light precisely and with increasedintensity to smaller areas of the document or object to be contactedand/or measured by the tips of the needles 6 and 7.

While the invention has been described with reference to severalparticular embodiments thereof, those skilled in the art will be able tomake the various modifications to the described embodiments of theinvention without departing from the true spirit and scope of theinvention. It is intended that all elements or steps which areinsubstantially different or perform substantially the same function insubstantially the same way to achieve the same result as what is claimedare within the scope of the invention.

For example, in some cases a single light emitting diode could beprovided, for example, between caliper legs 4 and 5, to illuminate thearea of the document or surface to be measured.

1. An illuminated caliper device, comprising: (a) a caliper assembly including i. first and second caliper legs each having a pointed tip and a pivot end, ii. first and second pivot elements attached to the pivot ends of the first and second caliper legs, respectively, the first and second pivot elements engaging each other to cause symmetrical opening and closing of the first and second caliper legs, iii. a pivot support and first and second pivot elements pivotally connecting the pivot ends of the first and second caliper legs to the pivot support; and (b) a battery housing attached to the pivot support; (c) a first light emitting diode mounted to the housing and coupled by a switch to first and second terminals of the battery, and having an optical axis extending along the first leg to an area of the surface containing a first point to be measured by the pointed tip of the first caliper leg, and a second light emitting diode coupled by the switch to the first and second terminals of the battery, the second light emitting diode being mounted to the housing and having an optical axis extending along the second leg to an area of the surface containing the second point to be measured by a pointed tip of the second caliper leg, (d) said diodes illuminating an area between and including said first and second points, wherein the first and second light emitting diodes emit light with intensity and color that illuminate the surface and the first and second point thereof without disrupting acquired night vision of a user.
 2. An illuminated caliper device, comprising: (a) a caliper assembly including i. first and second caliper legs each having a pointed tip and a pivot end, ii. first and second gear elements attached to the pivot ends of the first and second caliper legs, respectively, the first and second gear elements engaging each other to cause symmetrical opening and closing of the first and second caliper legs, iii. a pivot support and first and second pivot elements pivotally connecting the pivot ends of the first and second caliper legs to the pivot support; and (b) a battery housing attached to the pivot support; (c) a first light emitting diode mounted to the housing and coupled by a switch to first and second terminals of the battery, and having an optical axis extending along the first leg to an area of the surface containing a first point to be measured by the pointed tip of the first caliper leg, and a second light emitting diode coupled by the switch to the first and second terminals of the battery, the second light emitting diode being mounted to the housing and having an optical axis extending along the second leg to an area of the surface containing the second point to be measured by a pointed tip of the second caliper leg. (d) said diodes illuminating an area between and including said first and second points, wherein the first and second light emitting diodes emit light with intensity and color that illuminate the surface and the first and second point thereof without disrupting acquired night vision of a user. 